summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/paravirt_patch_32.c
AgeCommit message (Collapse)Author
2009-01-30x86/pvops: add a paravirt_ident functions to allow special patchingJeremy Fitzhardinge
Impact: Optimization Several paravirt ops implementations simply return their arguments, the most obvious being the make_pte/pte_val class of operations on native. On 32-bit, the identity function is literally a no-op, as the calling convention uses the same registers for the first argument and return. On 64-bit, it can be implemented with a single "mov". This patch adds special identity functions for 32 and 64 bit argument, and machinery to recognize them and replace them with either nops or a mov as appropriate. At the moment, the only users for the identity functions are the pagetable entry conversion functions. The result is a measureable improvement on pagetable-heavy benchmarks (2-3%, reducing the pvops overhead from 5 to 2%). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-08-15x86: coding style fixes to arch/x86/kernel/paravirt_patch_32.cPaolo Ciarrocchi
Before: total: 3 errors, 1 warnings, 49 lines checked After: total: 2 errors, 1 warnings, 49 lines checked paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/paravirt_patch_32.o.* a78eea4264723e18c49dcfbe0ee0aae7 /tmp/paravirt_patch_32.o.after a78eea4264723e18c49dcfbe0ee0aae7 /tmp/paravirt_patch_32.o.before Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08x86/paravirt: split sysret and sysexitJeremy Fitzhardinge
Don't conflate sysret and sysexit; they're different instructions with different semantics, and may be in use at the same time (at least within the same kernel, depending on whether its an Intel or AMD system). sysexit - just return to userspace, does no register restoration of any kind; must explicitly atomically enable interrupts. sysret - reloads flags from r11, so no need to explicitly enable interrupts on 64-bit, responsible for restoring usermode %gs Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com> Cc: xen-devel <xen-devel@lists.xensource.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-01-30x86: move patching code to arch-specific file.Glauber de Oliveira Costa
The core patching code for paravirt is sufficiently different among i386 and x86_64, and we move them to specific files. Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>